1. Field of the Invention
This invention relates to the manufacture of machine components with powdered metal--especially to improved methods of compressing powdered metals to form components such as bushings.
2. Background Information
The quest in manufacturing has long been the production of machine components in the most cost efficient manner that will yield high quality.
One method which is efficient for many components involves the compression of powdered metals in a die to accurate dimensions prior to sintering to the final metallurgical consistency.
One example of the many possible products of the powdered metal manufacturing technique is disclosed in U.S. Pat. No. 4,525,094, "Powdered Metal, Flanged Bushing for Securing Machine Elements to Shafts", June 25, 1985.
An earlier example of a bushing of commonly used configuration may be seen with reference to U.S. Pat. No. 3,677,583, "Bushing and Method of Manufacturing", July 18, 1972. Here, the bushings are tapered for use with hubs, each having a tapered internal wall corresponding to an external taper on an associated bushing. Screws are used in threaded holes formed between and intersecting the mating tapers to retain the bushing. This particular method of manufacture includes the steps of placing bushing blanks having the tapered surfaces together and drilling and tapping a single hole in the area of contact between them. Additional slots or grooves are formed on the periphery of each bushing blank, usually extending about one half the distance from one end of the blank to the other. These slots are also commonly formed by drilling, requiring an additional operation that adds to manufacturing costs.